The Erlanger chest pain evaluation protocol: a one-year experience with serial 12-lead ECG monitoring, two-hour delta serum marker measurements, and selective nuclear stress testing to identify and exclude acute coronary syndromes

Prevalence and Predictors of Obstructive Coronary Artery Disease in Nonlow-risk Acute Chest Pain Patients Who Rule Out for Myocardial Infarction in the High-sensitivity Troponin Era

OBJECTIVES

The best management approach for chest pain patients who rule out for myocardial infarction (MI) in the high-sensitivity troponin (hsTn) era remains elusive. Patients, especially those with nonlow clinical risk scores, are often referred for inpatient ischemic testing to uncover obstructive coronary artery disease (CAD). Whether the prevalence of obstructive CAD in this cohort is high enough to justify routine testing is not known.

METHODS

We conducted a retrospective cohort analysis of 1517 emergency department chest pain patients who ruled out for MI by virtue of a stable high-sensitivity troponin T (hsTnT) levels (defined as <5 ng/L intermeasurements increase) and were admitted for inpatient testing.

RESULTS

Abnormal ischemia evaluation (including 5.9% with evidence of fixed wall motion or perfusion defects) was 11.9%. Of those undergoing invasive angiography (n = 292), significant coronary stenoses (≥70% or unstable lesions) and multivessel CAD occurred in 16.8% and 5.5%, respectively. In a multivariate logistic regression model, known CAD, prior MI, chest pain character, mildly elevated hsTnT, and left ventricular ejection fraction <40% were predictive of an abnormal ischemia evaluation result, whereas electrocardiography findings and the modified History, EKG, Age, Risk factors, and troponin (HEART) score were not. Of note, 30-day adverse cardiac events were strikingly low at 0.4% with no deaths despite an overwhelming majority (>90%) of patients scoring intermediate or high on the modified HEART score.

CONCLUSIONS

A considerable percentage of acute chest pain patients who rule out for MI by hsTn had evidence of obstructive CAD, and the modified HEART score was not predictive of an abnormal ischemia evaluation.

Recommandations Formalisées d’Experts SRLF/SFMU : Prise en charge des états de mal épileptiques en préhospitalier, en structure d’urgence et en réanimation dans les 48 premières heures (A l’exclusion du nouveau-né et du nourrisson)

La Société de réanimation de langue française et la Société française de médecine d’urgence ont décidé d’élaborer de nouvelles recommandations sur la prise en charge de l’état mal épileptique (EME) avec l’ambition de répondre le plus possible aux nombreuses questions pratiques que soulèvent les EME : diagnostic, enquête étiologique, traitement non spécifique et spécifique. Vingt-cinq experts ont analysé la littérature scientifique et formulé des recommandations selon la méthodologie GRADE. Les experts se sont accordés sur 96 recommandations. Les recommandations avec le niveau de preuve le plus fort ne concernent que l’EME tonico-clonique généralisé (EMTCG) : l’usage des benzodiazépines en première ligne (clonazépam en intraveineux direct ou midazolam en intramusculaire) est recommandé, répété 5 min après la première injection (à l’exception du midazolam) en cas de persistance clinique. En cas de persistance 5 min après cette seconde injection, il est proposé d’administrer la seconde ligne thérapeutique : valproate de sodium, (fos-)phénytoïne, phénobarbital ou lévétiracétam. La persistance avérée de convulsions 30 min après le début de l’administration du traitement de deuxième ligne signe l’EMETCG réfractaire. Il est alors proposé de recourir à un coma thérapeutique au moyen d’un agent anesthésique intraveineux de type midazolam ou propofol. Des recommandations spécifiques à l’enfant et aux autres EME sont aussi énoncées.

Feasibility of unconstrained three-material decomposition: imaging an excised human heart using a prototype silicon photon-counting CT detector

Rationale and objectives

The purpose of this study was to evaluate the feasibility of unconstrained three-material decomposition in a human tissue specimen containing iodinated contrast agent, using an experimental multi-bin photon-counting silicon detector. It was further to evaluate potential added clinical value compared to a 1st-generation state-of-the-art dual-energy computed tomography system.

Materials and methods

A prototype photon-counting silicon detector in a bench-top setup for x-ray tomographic imaging was calibrated using a multi-material calibration phantom. A heart with calcified plaque was obtained from a deceased patient, and the coronary arteries were injected with an iodinated contrast agent mixed with gelatin. The heart was imaged in the experimental setup and on a 1st-generation state-of-the-art dual-energy computed tomography system. Projection-based three-material decomposition without any constraints was performed with the photon-counting detector data, and the resulting images were compared with those obtained from the dual-energy system.

Results

The photon-counting detector images show better separation of iodine and calcium compared to the dual-energy images. Additional experiments confirmed that unbiased estimates of soft tissue, calcium, and iodine could be achieved without any constraints.

Conclusion

The proposed experimental system could provide added clinical value compared to current dual-energy systems for imaging tasks where mix-up of iodine and calcium is an issue, and the anatomy is sufficiently small to allow iodine to be differentiated from calcium. Considering its previously shown count rate capability, these results show promise for future integration of this detector in a clinical CT scanner.

Key Points

• Spectral photon-counting detectors can solve some of the fundamental problems with conventional single-energy CT.

• Dual-energy methods can be used to differentiate iodine and calcium, but to do so must rely on constraints, since solving for three unknowns with only two measurements is not possible. Photon-counting detectors can improve upon these methods by allowing unconstrained three-material decomposition.

• A prototype photon-counting silicon detector with high count rate capability allows performing unconstrained three-material decomposition and qualitatively shows better differentiation of iodine and calcium than dual-energy CT.

Value of early rest myocardial perfusion imaging with SPECT in patients with chest pain and non-diagnostic ECG in emergency department

Evaluation of atypical presentation of angina chest pain in emergency department is difficult. Hospitalization of this patient may impose additional costs and waste the time, early discharge may lead to miss the patients. The aim of this study was to determine volubility of Single Photon Emission Computed Tomography (SPECT) in management of patients admitted to emergency department with atypical manifestations of angina pain, un-diagnostic Electrocardiogram (ECG) and negative enzyme. Half of 100 patients admitted to emergency department with atypical chest pain and un-diagnostic ECG who were candidate for admission, underwent ECG gated resting SPECT. According to the results of SPECT, low risk patient discharged after negative stress SPECT. All discharged patients were followed up for major cardiac events (cardiac death, nonfatal myocardial infarction and repeat admission for congestive heart failure) for 12 months. According to rest SPECT Myocardial Perfusion Imaging (MPI), about 70% of patients in case group was low risk and 30% of them had moderate or high risk. Case group represented lower hospitalization rate and lower need for Coronary Artery Angiography (CAG) in comparison with control group. Mean cost in case group was significantly lower than control group (175.15$ vs. 391.33$, P < 0.001). In one year follow- up no cases of mortality or major cardiovascular events as cardiac infraction were found in discharged patients in case group. our study showed that rest SPECT fulfillment in admitted patients in emergency department was validated method for assessing patients' risk which avoids unnecessary hospitalizations and additional costs.

Identifying Low-risk Patients for Early Discharge From Emergency Department Without Using Subjective Descriptions of Chest Pain: Insights From Providing Rapid Out of Hospital Acute Cardiovascular Treatment (PROACT) 3 and 4 Trials

BACKGROUND

Several accelerated diagnostic protocols (ADPs) have been developed to allow emergency department (ED) physicians to identify appropriate patients for safe early discharge after presentation with symptom of chest pain. Most ADPs require chest pain to be described and modify the algorithm based on the subjective chest pain characteristics. We investigated the performance of three established major ADPs simplified by eliminating the need for chest pain as a descriptor.

METHODS

We pooled patients from PROACT-3 and -4 trials, in which patients presenting to emergency medical services with chest pain or dyspnea were enrolled. The simplified Vancouver Chest Pain Rule (sVCPR), the simplified Emergency Department Assessment of Chest Pain Score (sEDACS) ADP and the Accelerated Diagnostic protocol to Assess Patients with chest pain using contemporary troponins as the only biomarker (ADAPT-ADP) were compared using the sensitivity, specificity, and positive and negative predictive values (NPV). The primary outcome of interest was 30-day major adverse cardiac events (MACE); the diagnosis of acute coronary syndrome (ACS) occurring within 30 days after ED presentation was also explored.

RESULTS

A total of 1,081 patients were included (median age = 67 years, 53% male, median GRACE score = 113) of which 222 ACS diagnoses and 150 cardiac events occurred within 30 days after index ED presentation. The sVCPR, sEDACS ≥ 3, and ADAPT-ADP, respectively, identified 9.7, 13.3, and 4.1% of patients as low risk with a sensitivity and NPV of 100% for the primary outcome of 30-day MACE. The sEDACS-ADP identified 24.2% of patients as low risk with a cut-point score of 4 (sensitivity of 98.0% and NPV of 98.8%). The sVCPR, sEDACS ≥ 3, and ADAPT-ADP, respectively, had NPVs of 98.1, 95.8, and 93.3% in identifying patients at higher risk of ACS diagnosis within 30 days after index ED visit.

CONCLUSION

The diagnostic protocols performed well without their chest pain characteristics component. Further studies are suggested to explore the performance of ADPs when these simplified ADPs are combined with high-sensitive troponin assays.

Noninvasive cardiac imaging in suspected acute coronary syndrome

Noninvasive cardiac imaging has an important role in the assessment of patients with acute-onset chest pain. In patients with suspected acute coronary syndrome (ACS), cardiac imaging offers incremental value over routine clinical assessment, the electrocardiogram, and blood biomarkers of myocardial injury, to confirm or refute the diagnosis of coronary artery disease and to assess future cardiovascular risk. This Review covers the current guidelines and clinical use of the common noninvasive imaging techniques, including echocardiography and stress echocardiography, computed tomography coronary angiography, myocardial perfusion scintigraphy, positron emission tomography, and cardiovascular magnetic resonance imaging, in patients with suspected ACS, and provides an update on the developments in noninvasive imaging techniques in the past 5 years.

Development and validation of a prediction rule for early discharge of low-risk emergency department patients with potential ischemic chest pain

Objectives:

Current guidelines emphasize that emergency department (ED) patients at low risk for potential ischemic chest pain cannot be discharged without extensive investigations or hospitalization to minimize the risk of missing acute coronary syndrome (ACS). We sought to derive and validate a prediction rule that permitted 20 to 30% of ED patients without ACS safely to be discharged within 2 hours without further provocative cardiac testing.

Methods:

This prospective cohort study enrolled 1,669 chest pain patients in two blocks in 2000–2003 (development cohort) and 2006 (validation cohort). The primary outcome was 30-day ACS diagnosis. A recursive partitioning model incorporated reliable and predictive cardiac risk factors, pain characteristics, electrocardiographic findings, and cardiac biomarker results.

Results:

In the derivation cohort, 165 of 763 patients (21.6%) had a 30-day ACS diagnosis. The derived prediction rule was 100.0% sensitive and 18.6% specific. In the validation cohort, 119 of 906 patients (13.1%) had ACS, and the prediction rule was 99.2% sensitive (95% CI 95.4–100.0) and 23.4% specific (95% CI 20.6–26.5). Patients have a very low ACS risk if arrival and 2-hour troponin levels are normal, the initial electrocardiogram is nonischemic, there is no history of ACS or nitrate use, age is &lt; 50 years, and defined pain characteristics are met. The validation of the rule was limited by the lack of consistency in data capture, incomplete follow-up, and lack of evaluation of the accuracy, comfort, and clinical sensibility of this clinical decision rule.

Conclusion:

The Vancouver Chest Pain Rule may identify a cohort of ED chest pain patients who can be safely discharged within 2 hours without provocative cardiac testing. Further validation across other centres with consistent application and comprehensive and uniform follow-up of all eligible and enrolled patients, in addition to measuring and reporting the accuracy of and comfort level with applying the rule and the clinical sensibility, should be completed prior to adoption and implementation.

Recommendations for the evaluation and management of observation services: a consensus white paper: the Society of Cardiovascular Patient Care

Observation Services (OS) was founded by emergency physicians in an attempt to manage "boarding" issues faced by emergency departments throughout the United States. As a result, OS have proven to be an effective strategy in reducing costs and decreasing lengths of stay while improving patient outcomes. When OS are appropriately leveraged for maximum efficiency, patients presenting to emergency departments with common disease processes can be effectively treated in a timely manner. A well-structured observation program will help hospitals reduce the number of inappropriate, costly inpatient admissions while avoiding the potential of inappropriate discharges. Observation medicine is a complicated multidimensional issue that has generated much confusion. This service is designed to provide the best possible patient care in a value-based purchasing environment where quality, cost, and patient satisfaction must continually be addressed. Observation medicine is a service not a status. Therefore, patients are admitted to the service as outpatients no matter whether they are placed in a virtual or dedicated observation unit. The key to a successful observation program is to determine how to maximize efficiencies. This white paper provides the reader with the foundational guidance for observational services. It defines how to set up an observational service program, which diagnoses are most appropriate for admission, and what the future holds. The goal is to help care providers from any hospital deliver the most appropriate level of treatment, to the most appropriate patient, in the most appropriate location while controlling costs.

Evaluation of a clinical tool for early etiology identification in status epilepticus

OBJECTIVES

Because early etiologic identification is critical to select appropriate specific status epilepticus (SE) management, we aim to validate a clinical tool we developed that uses history and readily available investigations to guide prompt etiologic assessment.

METHODS

This prospective multicenter study included all adult patients treated for SE of all but anoxic causes from four academic centers. The proposed tool is designed as a checklist covering frequent precipitating factors for SE. The study team completed the checklist at the time the patient was identified by electroencephalography (EEG) request. Only information available in the emergency department or at the time of in-hospital SE identification was used. Concordance between the etiology indicated by the tool and the determined etiology at hospital discharge was analyzed, together with interrater agreement.

RESULTS

Two hundred twelve patients were included. Concordance between the etiology hypothesis generated using the tool and the finally determined etiology was 88.7% (95% confidence interval (CI) 86.4-89.8) (κ = 0.88). Interrater agreement was 83.3% (95% CI 80.4-96) (κ = 0.81).

SIGNIFICANCE

This tool is valid and reliable for identification early the etiology of an SE. Physicians managing patients in SE may benefit from using it to identify promptly the underlying etiology, thus facilitating selection of the appropriate treatment.

Exercise echocardiography and multidetector computed tomography for the evaluation of acute chest pain

INTRODUCTION AND OBJECTIVES

Up to 4% of patients with acute chest pain, normal electrocardiogram, and negative troponins present major adverse cardiac events as a result of undiagnosed acute coronary syndrome. Our aim was to compare the diagnostic performance of multidetector computed tomography and exercise echocardiography in patients with a low-to-intermediate probability of coronary artery disease.

METHODS

We prospectively included 69 patients with acute chest pain, normal electrocardiogram, and negative troponins who underwent coronary tomography angiography and exercise echocardiography. Patients with coronary stenosis ≥ 50% or Agatston calcium score ≥ 400 on coronary tomography angiography or positive exercise echocardiography, or with inconclusive results, were admitted to rule out acute coronary syndrome.

RESULTS

An acute coronary syndrome was confirmed in 17 patients (24.6%). This was lower than the suspected 42% based on coronary tomography angiography (P<.05) and not significantly different than the suspected 29% based on the results of exercise echocardiography (P=.56). Exercise echocardiography was normal in up to 37% of patients with pathological findings on coronary tomography angiography. The latter technique provided a higher sensitivity (100% vs 82.3%; P=.21) but lower specificity (76.9% vs 88.4%; P=.12) than exercise echocardiography for the diagnosis of acute coronary syndrome, although without reaching statistical significance. Increasing the stenosis cutoff point to 70% increased the specificity of coronary tomography angiography to 88.4%, while maintaining high sensitivity.

CONCLUSIONS

Coronary tomography angiography offers a valid alternative to exercise echocardiography for the diagnosis of acute coronary syndrome among patients with low-to-intermediate probability of coronary artery disease. A combination of both techniques could improve the diagnosis of acute coronary syndrome.

Thrombolysis in myocardial infarction risk score in an observation unit setting

OBJECTIVE

The Thrombolysis in Myocardial Infarction (TIMI) score is a validated tool for risk stratification of acute coronary syndrome. We hypothesized that the TIMI risk score would be able to risk stratify patients in observation unit for acute coronary syndrome.

METHODS

STUDY DESIGN

Retrospective cohort study of consecutive adult patients placed in an urban academic hospital emergency department observation unit with an average annual census of 65,000 between 2004 and 2007. Exclusion criteria included elevated initial cardiac biomarkers, ST segment changes on ECG, unstable vital signs, or unstable arrhythmias. A composite of significant coronary artery disease (CAD) indicators, including diagnosis of myocardial infarction, percutaneous coronary intervention, coronary artery bypass surgery, or death within 30 days and 1 year, were abstracted via chart review and financial record query. The entire cohort was stratified by TIMI risk scores (0-7) and composite event rates with 95% confidence interval were calculated.

RESULTS

In total 2228 patients were analyzed. Average age was 54.5 years, 42.0% were male. The overall median TIMI risk score was 1. Eighty (3.6%) patients had 30-day and 119 (5.3%) had 1-year CAD indicators. There was a trend toward increasing rate of composite CAD indicators at 30 days and 1 year with increasing TIMI score, ranging from a 1.2% event rate at 30 days and 1.9% at 1 year for TIMI score of 0 and 12.5% at 30 days and 21.4% at 1 year for TIMI ≥ 4.

CONCLUSIONS

In an observation unit cohort, the TIMI risk score is able to risk stratify patients into low-, moderate-, and high-risk groups.

Risk stratification in chest pain patients undergoing nuclear stress testing: the Erlanger Stress Score

BACKGROUND

Studies have individually reported the relationship of age, cardiac risk factors, and history of preexisting coronary artery disease (CAD) for predicting acute coronary syndromes in chest pain patients undergoing cardiac stress testing. In this study, we investigate the interplay of all these factors on the incidence of acute coronary syndromes to develop a tool that may assist physicians in the selection of appropriate chest pain patients for stress testing.

METHODS

Retrospective analysis of a prospectively acquired database of consecutive chest pain patients undergoing nuclear stress testing. Backward stepwise logistic regression was used to develop a model for predicting risk of 30-day acute coronary events (ACE) using information obtained from age, sex, cardiac risk factors, and history of preexisting CAD.

RESULTS

A total of 800 chest pain patients underwent nuclear stress testing. ACE occurred in 74 patients (9.3%). Logistic regression analysis found only 6 factors predictive of ACE: age, male sex, preexisting CAD, diabetes, and hyperlipidemia. Area under the receiver operator characteristic curve of this model for predicting ACE was 0.767 (95% confidence interval, 0.719-0.815). There were no cases of ACE in the 173 patients with predicted probability estimates ≤2.5% (95% confidence interval, 0%-2.1%).

CONCLUSIONS

A regression model using age, sex, preexisting CAD, diabetes, and hyperlipidemia is predictive of 30-day ACE in chest pain patients undergoing nuclear stress testing. Prospective studies need to be performed to determine whether this model can assist physicians in the selection of appropriate low-to-intermediate risk chest pain patients for nuclear stress testing.

Is it prime time for "rapid comprehensive cardiopulmonary imaging" in the emergency department?

Reducing hospital admissions through improved risk stratification of patients with potential acute coronary syndrome represents a critical focus for reducing health care expenditure. Coronary computed tomographic angiography (CTA) has been used with increasing frequency as part of the evaluation of chest pain in the Emergency Department. In the appropriate group of patients at low to intermediate risk CTA appears to be an excellent evaluation strategy, safely and efficiently allowing for the rapid discharge of patients home.

Design and implementation of a stand-alone chest pain evaluation center within an academic emergency department

Chest pain is a common presenting symptom for emergency department (ED) patients; however, a thorough cardiac evaluation can be difficult to complete within the ED setting. Implementation of a stand-alone unit for the evaluation of chest pain may improve care for patients with chest pain. We designed a protocol for identifying patients without an acute coronary syndrome and with low-to-intermediate likelihood of obstructive coronary artery disease (CAD). These patients were monitored in a stand-alone chest pain evaluation center (CPEC) staffed with a small group of providers and tested for CAD, if necessary. In the first 6 weeks of operation, 181 patients were evaluated in the CPEC. The prevalence of CAD risk factors was low. Of the 181 patients, 159 (88%) were discharged home and 22 (12%) required admission to the hospital for further care. We compared the number of chest pain evaluations and admissions for first 6 weeks of operation to the same 6-week period from the 2 previous years. Whereas ED chest pain evaluations increased 66% over the 2-year time frame, the proportion admitted to the hospital decreased from 53% to 42% (P < 0.0001). In conclusion, evidence-based evaluation of chest pain in patients without acute coronary syndrome and with low-to-intermediate likelihood of obstructive CAD can result in the significant majority of patients being discharged from the ED. Creation of a stand-alone CPEC in an academic hospital was associated with a significant reduction in hospital admissions.

Improving risk stratification in patients with chest pain: the Erlanger HEARTS3 score

BACKGROUND

The HEART score uses elements from patient History, Electrocardiogram, Age, Risk Factors, and Troponin to obtain a risk score on a 0- to 10-point scale for predicting acute coronary syndromes (ACS). This investigation seeks to improve on the HEART score by proposing the HEARTS(3) score, which uses likelihood ratio analysis to give appropriate weight to the individual elements of the HEART score as well as incorporating 3 additional "S" variables: Sex, Serial 2-hour electrocardiogram, and Serial 2-hour delta troponin during the initial emergency department valuation.

METHODS

This is a retrospective analysis of a prospectively acquired database consisting of 2148 consecutive patients with non-ST-segment elevation chest pain. Interval analysis of likelihood ratios was performed to determine appropriate weighting of the individual elements of the HEART(3) score. Primary outcomes were 30-day ACS and myocardial infarction.

RESULTS

There were 315 patients with 30-day ACS and 1833 patients without ACS. Likelihood ratio analysis revealed significant discrepancies in weight of the 5 individual elements shared by the HEART and HEARTS(3) score. The HEARTS(3) score outperformed the HEART score as determined by comparison of areas under the receiver operating characteristic curve for myocardial infarction (0.958 vs 0.825; 95% confidence interval difference in areas, 0.105-0.161) and for 30-day ACS (0.901 vs 0.813; 95% confidence interval difference in areas, 0.064-0.110).

CONCLUSION

The HEARTS(3) score reliably risk stratifies patients with chest pain for 30-day ACS. Prospective studies need to be performed to determine if implementation of this score as a decision support tool can guide treatment and disposition decisions in the management of patients with chest pain.

Diagnostic accuracy of a point-of-care troponin I assay for acute myocardial infarction within 3 hours after presentation in early presenters to the emergency department with chest pain

BACKGROUND

Guidelines recommend that serial cardiac marker testing to rule out acute myocardial infarction (AMI) be performed for 8 to 12 hours after symptom onset. We aim to determine the diagnostic accuracy of a contemporary point-of-care (POC) troponin I (TnI) assay within 3 hours for patients presenting within 8 hours of symptom onset.

METHODS

The MIDAS study collected blood from patients presenting with suspected acute coronary syndrome at presentation and at 90 minutes, 3 hours, and 6 hours in whom the emergency physician planned an objective cardiac ischemia evaluation. Criterion standard diagnoses were adjudicated by experienced clinicians using all available medical records per American Heart Association/American College of Cardiology criteria. Reviewers were blinded to the investigational marker, Cardio3 TnI POC. The Cardio3 TnI reference value was defined as >0.05 ng/mL. Measures of diagnostic accuracy are presented with 95% CI.

RESULTS

A total of 858 of 1107 patients met the inclusion criteria. The study cohort had 476 men (55.5%) with median age of 57.0 years (interquartile range 48.0-67.0 years). Median time from symptom onset to initial blood draw was 3.9 hours (interquartile range 2.7-5.2 hours). Acute myocardial infarction was diagnosed in 82 patients (9.6%). The sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio over 3 hours were 84.1, 93.4, 12.8, and 0.17, respectively. There was no significant improvement in diagnostic accuracy associated with adding 6-hour serial testing to the 3-hour sample.

CONCLUSION

In suspected patients with acute coronary syndrome presenting to the emergency department within 8 hours of symptom onset, 3 hours of serial testing with the Cardio3 TnI POC platform provides similar diagnostic accuracy for AMI as longer periods.

Critical pathways for post-emergency outpatient diagnosis and treatment: tools to improve the value of emergency care

The decision to admit a patient to the hospital after an emergency department (ED) visit is expensive, frequently not evidence-based, and variable. Outpatient critical pathways are a promising approach to reduce hospital admission after emergency care. Critical pathways exist to risk stratify patients for potentially serious diagnoses (e.g., acute myocardial infarction [AMI]) or evaluate response to therapy (e.g., community-acquired pneumonia) within a short time period (i.e., less than 36 hours), to determine if further hospital-based acute care is needed. Yet, such pathways are variably used while many patients are admitted for conditions for which they could be treated as outpatients. In this article, the authors propose a model of post-ED critical pathways, describe their role in emergency care, list common diagnoses that are amenable to critical pathways in the outpatient setting, and propose a research agenda to address barriers and solutions to increase the use of outpatient critical pathways. If emergency providers are to routinely conduct rapid evaluations in outpatient or observation settings, they must have several conditions at their disposal: 1) evidence-based tools to accurately risk stratify patients for protocolized care, 2) systems of care that reliably facilitate workup in the outpatient setting, and 3) a medical environment conducive to noninpatient pathways, with aligned risks and incentives among patients, providers, and payers. Increased use of critical pathways after emergency care is a potential way to improve the value of emergency care.

Upstream treatment of acute coronary syndrome in the ED

Rapid risk stratification, selection of downstream management options, and institution of initial pharmacotherapy are essential to ensure that patients admitted to the emergency department with acute coronary syndromes receive optimal care. A broad range of antiplatelet and antithrombotic medications is available that permits tailoring of initial pharmacotherapy to each patient's risk status. In the urgent setting, thienopyridines (clopidogrel and prasugrel) carry limitations including response variability and increased risk for bleeding in patients requiring subsequent coronary artery bypass graft surgery. Glycoprotein IIb-IIIa receptor inhibitors, although they are highly effective in preventing ischemic events, must be used with care to reduce bleeding risk. Bivalirudin, a relatively new direct thrombin inhibitor, represents another upstream option but is costly and does not have approval for this indication. Simplified institutional management paradigms can streamline the process of selecting appropriate pharmacotherapy and aid in care delivery that will optimize patient outcomes.

Incremental diagnostic value of regional left ventricular function over coronary assessment by cardiac computed tomography for the detection of acute coronary syndrome in patients with acute chest pain: from the ROMICAT trial

BACKGROUND

The incremental value of regional left ventricular function (LVF) over coronary assessment to detect acute coronary syndrome (ACS) is uncertain.

METHODS AND RESULTS

We analyzed 356 patients (mean age, 53+/-12 years; 62% men) with acute chest pain and inconclusive initial emergency department evaluation. Patients underwent 64-slice contrast-enhanced cardiac computed tomography before hospital admission. Caregivers and patients remained blinded to the results. Regional LVF and presence of coronary atherosclerotic plaque and significant stenosis (>50%) were separately assessed by 2 independent readers. Incremental value of regional LVF to predict ACS was determined in the entire cohort and in subgroups of patients with nonobstructive coronary artery disease, inconclusive assessment for stenosis (defined as inability to exclude significant stenosis due to calcium or motion), and significant stenosis. During their index hospitalization, 31 patients were ultimately diagnosed with ACS (8 myocardial infarction, 22 unstable angina), of which 74% (23 patients) had regional LV dysfunction. Adding regional LVF resulted in a 10% increase in sensitivity to detect ACS by cardiac computed tomography (87%; 95% confidence interval, 70% to 96%) and significantly improved the overall accuracy (c-statistic: 0.88 versus 0.94 and 0.79 versus 0.88, for extent of plaque and presence of stenosis, respectively; both P<0.03). The diagnostic accuracy of regional LVF for detection of ACS has 89% sensitivity and 86% specificity in patients with significant stenosis (n=33) and 60% sensitivity and 86% specificity in patients with inconclusive coronary computed tomographic angiography (n=33).

CONCLUSIONS

Regional LVF assessment at rest improves diagnostic accuracy for ACS in patients with acute chest pain, especially in those with coronary artery disease and thus may be helpful to guide further management in patients at intermediate risk for ACS.

Outcomes associated with small changes in normal-range cardiac markers

INTRODUCTION

Troponin concentrations rising above an institutional cutpoint are used to define acute myocardial necrosis, yet it is uncertain what outcomes are associated with fluctuations in troponin that do not exceed this level. We evaluate the association between troponin fluctuations below an institutional upper limit of normal and acute coronary syndrome (ACS).

MATERIALS AND METHODS

This was a post hoc analysis of the Internet tracking registry of ACS (i*trACS), which describes patients presenting to emergency departments (EDs) with suspected ACS across the spectrum of risk. Patients were included in this registry if they were at least 18 years old and had suspected ACS at the time of their ED visit. Inclusions in this analysis required that patients had at least 1 cardiac marker (creatine kinase-MB [CK-MB], troponin T, or troponin I) drawn twice within 6 hours of presentation, with both measures being below the institution's upper limit of normal. A marker change was defined as either an increase or decrease that exceeded 15% of the institutional upper limit of normal. Acute coronary syndrome was defined as a positive stress test, documented myocardial infarction, coronary revascularization, or death within 30 days of their ED admission.

RESULTS

Of 17,713 patient visits, 2162 met inclusion and exclusion criteria. There were 1872 patient visits with 2 troponin results and 1312 with 2 CK-MB results. Patient visits with increasing troponin had increased odds of ACS compared with those with stable troponin levels (odds ratio, 3.6; 95% confidence interval, 1.4-9.2). Changing CK-MB and decreasing troponin were not associated with increased odds of ACS.

CONCLUSIONS

Small increases in troponin concentration below the upper limit of normal are associated with increased odds of ACS.

Emergency department and office-based evaluation of patients with chest pain

The management of patients with chest pain is a common and challenging clinical problem. Although most of these patients do not have a life-threatening condition, the clinician must distinguish between those who require urgent management of a serious problem such as acute coronary syndrome (ACS) and those with more benign entities who do not require admission. Although clinical judgment continues to be paramount in meeting this challenge, new diagnostic modalities have been developed to assist in risk stratification. These include markers of cardiac injury, risk scores, early stress testing, and noninvasive imaging of the heart. The basic clinical tools of history, physical examination, and electrocardiography are currently widely acknowledged to allow early identification of low-risk patients who have less than 5% probability of ACS. These patients are usually initially managed in the emergency department and transitioned to further outpatient evaluation or chest pain units. Multiple imaging strategies have been investigated to accelerate diagnosis and to provide further risk stratification of patients with no initial evidence of ACS. These include rest myocardial perfusion imaging, rest echocardiography, computed tomographic coronary angiography, and cardiac magnetic resonance imaging. All have very high negative predictive values for excluding ACS and have been successful in reducing unnecessary admissions for patients at low to intermediate risk of ACS. As patients with acute chest pain transition from the evaluation in the emergency department to other outpatient settings, it is important that all clinicians involved in the care of these patients understand the tools used for assessment and risk stratification.

Comprehensive standardized data definitions for acute coronary syndrome research in emergency departments in Australasia

Patients with chest discomfort or other symptoms suggestive of acute coronary syndrome are one of the most common categories seen in many Emergency Departments (EDs). Although the recognition of patients at high risk of acute coronary syndrome has improved steadily, identifying the majority of chest pain presentations who fall into the low-risk group remains a challenge. Research in this area needs to be transparent, robust, applicable to all hospitals from large tertiary centres to rural and remote sites, and to allow direct comparison between different studies with minimum patient spectrum bias. A standardized approach to the research framework using a common language for data definitions must be adopted to achieve this. The aim was to create a common framework for a standardized data definitions set that would allow maximum value when extrapolating research findings both within Australasian ED practice, and across similar populations worldwide. Therefore a comprehensive data definitions set for the investigation of non-traumatic chest pain patients with possible acute coronary syndrome was developed, specifically for use in the ED setting. This standardized data definitions set will facilitate 'knowledge translation' by allowing extrapolation of useful findings into the real-life practice of emergency medicine.

Coronary computed tomography angiography for early triage of patients with acute chest pain: the ROMICAT (Rule Out Myocardial Infarction using Computer Assisted Tomography) trial

OBJECTIVES

This study was designed to determine the usefulness of coronary computed tomography angiography (CTA) in patients with acute chest pain.

BACKGROUND

Triage of chest pain patients in the emergency department remains challenging.

METHODS

We used an observational cohort study in chest pain patients with normal initial troponin and nonischemic electrocardiogram. A 64-slice coronary CTA was performed before admission to detect coronary plaque and stenosis (>50% luminal narrowing). Results were not disclosed. End points were acute coronary syndrome (ACS) during index hospitalization and major adverse cardiac events during 6-month follow-up.

RESULTS

Among 368 patients (mean age 53 +/- 12 years, 61% men), 31 had ACS (8%). By coronary CTA, 50% of these patients were free of coronary artery disease (CAD), 31% had nonobstructive disease, and 19% had inconclusive or positive computed tomography for significant stenosis. Sensitivity and negative predictive value for ACS were 100% (n = 183 of 368; 95% confidence interval [CI]: 98% to 100%) and 100% (95% CI: 89% to 100%), respectively, with the absence of CAD and 77% (95% CI: 59% to 90%) and 98% (n = 300 of 368, 95% CI: 95% to 99%), respectively, with significant stenosis by coronary CTA. Specificity of presence of plaque and stenosis for ACS were 54% (95% CI: 49% to 60%) and 87% (95% CI: 83% to 90%), respectively. Only 1 ACS occurred in the absence of calcified plaque. Both the extent of coronary plaque and presence of stenosis predicted ACS independently and incrementally to Thrombolysis In Myocardial Infarction risk score (area under curve: 0.88, 0.82, vs. 0.63, respectively; all p < 0.0001).

CONCLUSIONS

Fifty percent of patients with acute chest pain and low to intermediate likelihood of ACS were free of CAD by computed tomography and had no ACS. Given the large number of such patients, early coronary CTA may significantly improve patient management in the emergency department.

A comprehensive electrocardiogram-gated 64-slice multidetector computed tomography imaging protocol to visualize the coronary arteries, thoracic aorta, and pulmonary vasculature in a single breath hold

OBJECTIVES

Advances in computed tomography technology may permit the evaluation of coronary disease, aortic dissection, and pulmonary embolism with a single contrast bolus and breath hold. We sought to determine whether 64-slice computed tomography angiography (CTA) allows for simultaneous visualization of the coronary arteries, thoracic aorta, and pulmonary arteries (coronary, aorta, pulmonary [CAP]) with image quality comparable to routine CTA protocols.

MATERIALS AND METHODS

We prospectively enrolled 20 patients who underwent CAP CTA. Image quality of CAP CTA was assessed qualitatively and quantitatively and compared with dedicated coronary (n = 20) and pulmonary (n = 10) CTA data sets using matched controls.

RESULTS

The mean amount of contrast and radiation dose was 132 +/- 10 mL and 17.8 +/- 1.8 mSv, 78 +/- 9 mL and 13.7 +/- 3.4 mSv, and 135 mL and 11.9 +/- 1.5 mSv for CAP CTA, coronary CTA, and pulmonary CTA, respectively (P = 0.001). There was no difference in overall image quality (P = 0.88), presence of motion artifacts (P = 0.40), or enhancement of the proximal coronary arteries (median [interquartile range for contrast-noise ratio was 12.5 9.9-15.2 vs 13.1 10.3-16.9; P = 0.17]) or thoracic aorta (264 [113-326] vs 245 [107-295]; P = 0.34) between CAP CTA and the dedicated coronary CTA, respectively. However, contrast attenuation was higher in the pulmonary arteries with CAP CTA (363 [253-424]) versus the standard pulmonary CTA protocol (235 [182-269]; P = 0.0001).

CONCLUSIONS

: Using an individually tailored single contrast injection, CAP CTA permits simultaneous visualization of the coronary arteries, thoracic aorta, and pulmonary arteries with excellent image quality. Further research is necessary to determine whether this protocol may enhance triage of patients with undifferentiated acute chest pain.

An analysis of the Association of Society of Chest Pain Centers Accreditation to American College of Cardiology/American Heart Association non-ST-segment elevation myocardial infarction guideline adherence

STUDY OBJECTIVE

Since 2003, the Society of Chest Pain Centers (SCPC) has provided hospital accreditation for acute coronary syndrome care processes. Our objective is to evaluate the association between SCPC accreditation and adherence to the American College of Cardiology/American Heart Association (ACC/AHA) evidence-based guidelines for non-ST-segment elevation myocardial infarction (NSTEMI). The secondary objective is to describe the clinical outcomes and the association with accreditation.

METHODS

We conducted a secondary analysis of data from patients with NSTEMI enrolled in the Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes With Early Implementation of the ACC/AHA Guidelines (CRUSADE) quality improvement initiative in 2005. The analysis explored differences between SCPC-accredited and nonaccredited hospitals in evidence-based therapy given within the first 24 hours (including aspirin, beta-blocker, glycoprotein IIb/IIIa inhibitors, heparin, and ECG within 10 minutes).

RESULTS

Of 33,238 patients treated at 21 accredited hospitals and 323 nonaccredited hospitals, those at SCPC-accredited centers (n=3,059) were more likely to receive aspirin (98.1% versus 95.8%; odds ratio [OR] 1.73; 95% confidence interval [CI] 1.06 to 2.83) and beta-blockers (93.4% versus 90.6%; OR 1.68; 95% CI 1.04 to 2.70) within 24 hours than patients at non-SCPC-accredited centers (n=30,179). No difference was observed in obtaining a timely ECG (40.4% versus 35.2%; OR 1.28; 95% CI 0.98 to 1.67), administering a glycoprotein IIb/IIIa inhibitor (OR 1.30; 95% CI 0.93 to 1.80), or administering heparin (OR 1.12; 95% CI 0.74 to 1.70). Also, there was no significant difference in risk-adjusted mortality for patients treated at SCPC hospitals versus nonaccredited hospitals (3.4% versus 3.5%; adjusted OR 1.17; 95% CI 0.88 to 1.55).

CONCLUSION

SCPC-accredited hospitals had higher NSTEMI ACC/AHA evidence-based guideline adherence in the first 24 hours of care on 2 of the 5 measures. No difference in outcomes was observed. Further studies are needed to better understand the association between SCPC accreditation and improved care for patients with acute coronary syndrome.

Emergency cardiac CT for suspected acute coronary syndrome: qualitative and quantitative assessment of coronary, pulmonary, and aortic image quality

OBJECTIVE

The purpose of this study was to determine whether a dedicated coronary CT protocol provides adequate contrast enhancement and artifact-free depiction of coronary, pulmonary, and aortic circulation.

MATERIALS AND METHODS

Dedicated coronary 64-MDCT data sets of 50 patients (27 men; mean age, 54 +/- 12.4 years) consecutively admitted from the emergency department with suspected acute coronary syndrome were analyzed. Two independent observers graded overall coronary arterial image quality and qualitative and quantitative contrast opacification, motion, and streak artifacts within the pulmonary arteries and aorta.

RESULTS

Coronary image quality was excellent in 48 patients (96%) and moderate in two patients (4%). Eleven left main and 22 left upper lobar pulmonary arteries were not visualized. Qualitative evaluation showed pulmonary arterial tree opacification to be excellent except for the right and left lower lateral and posterior segmental branches (52-54% rate of poor opacification). Quantitative evaluation showed four central (8%), six lobar (8%), and 206 segmental (29%) branches had poor contrast opacification (< 200 HU). Nineteen right upper lobar arteries (38%) were slightly and one was severely affected by streak artifact. At the segmental pulmonary artery level, marked differences in contrast enhancement were detected between the upper (292 +/- 72 HU) and both the middle (249 +/- 85 HU) and the lower lobes (248 +/- 76 HU) (p < 0.01). Mean aortic opacification was 300 +/- 34 HU with excellent contrast homogeneity without severe motion or streak artifacts.

CONCLUSION

In the evaluation of patients presenting to the emergency department with suspected acute coronary syndrome, a dedicated coronary CT protocol enables excellent assessment of the coronary arteries and proximal ascending aorta but does not depict the pulmonary vasculature well enough for exclusion of pulmonary embolism.

Value of information of a clinical prediction rule: informing the efficient use of healthcare and health research resources

OBJECTIVES

The aim of this study was to estimate the potential cost-effectiveness and expected value of perfect information of a recently derived clinical prediction rule for patients presenting to emergency departments with chest discomfort.

METHODS

A decision analytic model was constructed to compare the Early Disposition Prediction Rule (EDPR) with the current standard of care. Results were used to calculate the potential cost-effectiveness of the EDPR, as well as the Value of Information in conducting further research. Study subjects were adults presenting with chest discomfort to two urban emergency departments in Vancouver, British Columbia, Canada. The clinical prediction rule identifies patients who are eligible for early discharge within 3 hours of presentation to the emergency department. The outcome measure used was inappropriate emergency department discharge of patients with acute coronary syndrome (ACS).

RESULTS

The incremental cost-effectiveness ratio of the EDPR in comparison to usual care was (negative) $2,999 per inappropriate ACS discharge prevented, indicating a potential cost-savings in introducing the intervention. The expected value of perfect information was $16.3 million in the first year of implementation, suggesting a high benefit from conducting further research to validate the decision rule.

CONCLUSIONS

The EDPR is likely to be cost-effective; however, given the high degree of uncertainty in the estimates of costs and patient outcomes, further research is required to inform the decision to implement the intervention. The potential health and monetary benefits of this clinical prediction rule outweigh the costs of doing further research.